#include "S_Box.hpp"


#if ! defined TABLED_RIJNDAEL_SBOX

/*---------------------------------------------*
 * Calculates anti-logarithm on Galois field
 *---------------------------------------------*/

static
byte
galois_alog( byte x )
{
    byte atb = 1;

    while ( x-- )
    {
        byte tmp = atb << 1;

        if ( atb & 0x80 )
            tmp ^= 0x1b;
        atb ^= tmp;
    }

    return atb;
}


/*---------------------------------------------*
 * Calculates logarithm on Galois field
 *---------------------------------------------*/

static
byte
galois_log( byte x )
{
    if ( x == 1 )
        return 0;

    byte atb = 1,
         res = 0;

    do
    {
        byte tmp = atb << 1;

        if ( atb & 0x80 )
            tmp ^= 0x1b;
        atb ^= tmp;
    } while ( ++res && atb != x );

    return res;
}


/*---------------------------------------------*
 * Calculates multiplicative inverse
 *---------------------------------------------*/

static
byte
galois_mulinv( byte x )
{
    return x ? galois_alog( ~ galois_log( x ) ) : 0;
}


/*---------------------------------------------*
 * Calculates an element of the Rijndael S-Box
 *---------------------------------------------*/

template< >
byte
S_Box< false >::calc_element( byte x ) const
{
    x  = galois_mulinv( x );
    x ^=   ( ( x << 1 ) | ( x >> 7 ) )
         ^ ( ( x << 2 ) | ( x >> 6 ) )
         ^ ( ( x << 3 ) | ( x >> 5 ) )
         ^ ( ( x << 4 ) | ( x >> 4 ) );

    return x ^ 0x63;
}


/*---------------------------------------------*
 * Calculates an element of the inverse of the Rijndael S-Box
 *---------------------------------------------*/

template< >
byte
S_Box< true >::calc_element( byte x ) const
{
    x ^= 0x63;
    x  =   ( ( x << 1 ) | ( x >> 7 ) )
         ^ ( ( x << 3 ) | ( x >> 5 ) )
         ^ ( ( x << 6 ) | ( x >> 2 ) );

    return galois_mulinv( x );
}


#else // TABLED_RIJNDAEL_SBOX

/*---------------------------------------------*
 * Rijndael S-box and its inverse as static array
 *---------------------------------------------*/

template< > byte const S_Box< false >::s_sbox[ ] =
                        { 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
                          0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
                          0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
                          0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
                          0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc,
                          0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
                          0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a,
                          0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
                          0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
                          0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
                          0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b,
                          0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
                          0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85,
                          0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
                          0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
                          0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
                          0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17,
                          0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
                          0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88,
                          0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
                          0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
                          0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
                          0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9,
                          0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
                          0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6,
                          0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
                          0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
                          0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
                          0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94,
                          0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
                          0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
                          0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };

template< > byte const S_Box< true >::s_sbox[ ] =
                        { 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38,
                          0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
                          0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87,
                          0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
                          0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d,
                          0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
                          0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2,
                          0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
                          0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16,
                          0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
                          0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda,
                          0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
                          0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a,
                          0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
                          0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02,
                          0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
                          0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea,
                          0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
                          0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85,
                          0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
                          0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89,
                          0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
                          0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20,
                          0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
                          0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31,
                          0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
                          0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d,
                          0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
                          0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0,
                          0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
                          0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26,
                          0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d };

#endif


/*
 * Local variables:
 * tab-width: 4
 * indent-tabs-mode: nil
 * End:
 */
